Luminous devices, packages and systems containing the same, and fabricating methods thereof

ABSTRACT

The present invention is directed to a vertical-type luminous device and high through-put methods of manufacturing the luminous device. These luminous devices can be utilized in a variety of luminous packages, which can be placed in luminous systems. The luminous devices are designed to maximize light emitting efficiency and/or thermal dissipation. Other improvements include an embedded zener diode to protect against harmful reverse bias voltages.

RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.13/630,519, filed Sep. 28, 2012, which is a continuation of U.S. patentapplication Ser. No. 13/414,928, filed Mar. 8, 2012, now U.S. Pat. No.8,278,668, which is a continuation of U.S. patent application Ser. No.13/111,229, filed May 19, 2011, now U.S. Pat. No. 8,174,030, which is adivisional of U.S. patent application Ser. No. 12/386,882, filed on Apr.24, 2009, now U.S. Pat. No. 7,968,355, which claims the benefit ofKorean Patent Application No. 2008-0038970 filed on Apr. 25, 2008, thedisclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to luminous devices, packages and systemscontaining the luminous devices, and methods of fabricating the luminousdevices and packages containing it. More particularly, the presentinvention relates to light emitting devices, such as light emittingdiodes and semiconductor lasers.

BACKGROUND OF THE INVENTION

Luminous devices, such as light emitting diodes and semiconductorlasers, have a variety of uses. In particular, light emitting diodes(“LEDs”) have garnered significant interest as a result of certainbenefits over incandescent light bulbs and fluorescent lights. Thesebenefits include increased longevity and lower electricity requirements.For example, many LCD screens utilize LED's. In addition to light uses,LEDs can also be used for sterilization and disinfection. Similarly,semiconductor lasers, such as laser diodes, have also garneredsignificant interest, since they can be used in a variety ofapplications. For example, semiconductor lasers can be used in laserprinters, CD/DVD players and optical computing.

SUMMARY OF THE INVENTION

The present invention is directed to luminous devices having aconductive substrate. These luminous devices can be capable of (i)emitting light primarily towards at least one predetermined direction,(ii) increasing the emission of reflected light, or (iii) thermallyconducting heat away from the luminous device, or any combinationthereof.

One embodiment of the present invention is directed to a first generalmethod of manufacturing a luminous device. The method includes: formingat least one luminous structure on a first substrate; forming apatterned insulation layer on the luminous structure, wherein theinsulation layer includes a recess exposing a portion of the secondcladding layer; forming a first electrode layer in the recess and on atleast a portion of the insulation layer; attaching at least a portion ofa surface of the first electrode layer to a second conductive substrate;removing the first substrate to expose at least one surface of the firstcladding layer; and forming a second electrode on an exposed surface ofthe first cladding layer of the luminous structure. The luminousstructure includes a first cladding layer, at least a portion of whichis on the first substrate, an active layer on the first cladding layer,a second cladding layer on the active layer, and at least one inclinedside surface comprising the exposed sides of the first cladding layer,the active layer and the second cladding layer. The method can furtherinclude separating the second substrate and regions around the luminousstructure to form at least one luminous device comprising at least oneluminous structure

In another embodiment, the first general method can further include thestep of forming at least one groove separating at least the secondcladding layer and the active layer while providing at least acontinuous portion of the first cladding layer, wherein one portion ofthe groove defines a major portion of the luminous structure and anotherportion of the groove defines a minor portion of the luminous structure.In this embodiment, (i) the recess in the insulation layer can be formedon the major portion of the luminous structure and (ii) the forming asecond electrode step can be modified to include forming a secondelectrode on the exposed surface of the first cladding layer of theminor portion. More than one straight groove and/or one or more curvedgrooves can be formed in the luminous structure to provide anisland-type minor portion of the luminous structure.

In another embodiment, the first general method can further include thestep of forming a convex structure from the first cladding layer, andthe second electrode can then be formed on the convex structure. Thisadditional step can be applied to any of the embodiments describedherein. For example, this additional step can be applied to the groovedembodiment described in the previous paragraph by forming a convexstructure from the first cladding layer of the major portion of theluminous structure.

In another embodiment, the first general method (and any of thepreviously described embodiments) can be modified by utilizing a secondconductive substrate including a zener diode comprising a doped regionof the conductive substrate, wherein the doped region has a conductivetype opposite to the conductive type of the second conductive substrate,and wherein only the doped region is in electrical communication withthe first electrode.

Another embodiment of the present invention is directed to a secondgeneral method of manufacturing a luminous device having a through via.This method includes: forming at least one luminous structure on a firstsubstrate, the luminous structure comprising a first cladding layer onthe first substrate, an active layer on the first cladding layer, asecond cladding layer on the active layer, at least one side surfacecomprising the exposed sides of the layers, and at least one grooveseparating at least the second cladding layer and the active layer whileprovide at least a continuous portion of the first cladding layer,wherein one portion of the groove defines a major portion of theluminous structure and another portion of the groove defines a minorportion of the luminous structure; forming a patterned insulation layeron the luminous structure, wherein the insulation layer includes arecess to expose a portion of the second cladding layer in the majorportion of the luminous structure; forming a patterned first electrodelayer in the recess and on at least a portion of the insulation layer,wherein the first electrode layer is discontinuous in the groove regionto electrically isolate the minor portion from the major portion;forming an insulated through via contact extending from the firstelectrode layer to the first cladding layer of the minor portion of theluminous structure; attaching at least a portion of a surface of thefirst electrode layer to a second conductive substrate, wherein thesecond conductive substrate comprises a patterned conductiveintermediate layer having a first portion for attachment to the surfaceof the first electrode layer corresponding to the recess and a secondportion for electrical communication with the through via contact;removing the first substrate to expose at least one surface of the firstcladding layer; and separating the second substrate and regions aroundthe luminous structure to form at least one luminous device comprisingat least one luminous structure.

In another embodiment, the second general method can be modified so thatthe second conductive substrate comprises (i) a zener diode having firstdoped region and (ii) a second doped region extending through the secondconductive substrate, wherein the first portion of the patternedconductive intermediate layer is disposed on the first doped region ofthe second conductive substrate and attached to at least a portion ofthe surface of the first electrode layer corresponding to the recess,and wherein the second portion of the patterned conductive intermediatelayer is disposed on and within the second doped region of theconductive substrate and contacting the through via contact of the minorportion of the luminous structure.

In another embodiment, the second general method can be modified so thatthe second conductive substrate comprises (i) a zener diode having afirst doped region, a (ii) an insulated through via contact extendingthrough the second conductive substrate, wherein the first portion ofthe patterned conductive intermediate layer is disposed on and withinthe first doped region of the conductive substrate and attached to atleast a portion of the surface of the first electrode layercorresponding to the recess, and wherein the second portion of thepatterned conductive intermediate layer is disposed on the through viacontact of the conductive substrate and contacting the through viacontact of the minor portion of the luminous structure.

The present invention is also directed to luminous devices obtained fromany of the methods described above or a combination any steps thereof.

Another embodiment of the present invention is directed to a firstgeneral luminous device. This luminous device includes: a luminousstructure having a light emitting first surface, a second surface, atleast one side surface inclined at an angle compared to the secondsurface, an active layer having a first surface and a second surface, afirst cladding layer on the first surface of the active layer and alsoproviding the first surface of the luminous structure, and a secondcladding layer on the second surface of the active layer and alsoproviding the second surface of the luminous structure; an insulationlayer on at least a portion of the at least one side surface and thesecond surface of the luminous structure, wherein the insulating layerincludes a recess exposing at least a portion of the second claddinglayer; first and second electrodes connected to the luminous structure,wherein the first electrode is in electrical communication with thesecond cladding layer and disposed on at least a substantial portion ofthe insulation layer; and a conductive substrate attached to at least aportion of a surface of the first electrode.

In another embodiment, the first general device can further include agroove along the second surface of the luminous structure to provide amajor portion of the luminous structure and a minor portion of theluminous structure, wherein the groove separates at least the secondcladding layer and the active layer of the luminous structure whileprovide at least a continuous portion of the first cladding layer, andwherein the second electrode is located on a first surface of the minorportion of the luminous structure. More than one straight groove and/orone or more curved grooves can be formed in the luminous structure toprovide an island-type minor portion of the luminous structure.

In another embodiment, the first general device can include a firstcladding layer having a convex-shaped lens portion. This additionalstructural limitation can be included in any of the embodimentsdescribed herein. For example, the major portion of the grooved devicecan include a portion of the first cladding layer having a convex shape.

In another embodiment, any of the previously described embodiments canhave a conductive substrate further comprising a zener diode. The zenerdiode can include a doped region of the conductive substrate, whereinonly the doped region is in electrical communication with the firstelectrode.

Another embodiment of the present invention is directed to a secondgeneral luminous device. This device includes: a luminous structurehaving a light-emitting first surface, at least one side surface, and asecond surface; a patterned insulation layer on the second surface andat least a portion of the at least one side surface of the luminousstructure, wherein the insulation layer includes a recess exposing aportion of the second surface; a substrate supporting the luminousstructure; a first electrical conduit for connection to a power source;a second electrical conduit for connection to the power source; a meansfor electrically connecting the first surface of the luminous structurewith the first electrical conduit; and a means for electricallyconnecting the second surface of the luminous structure with the firstelectrical conduit and for reflecting light impinging on the at leastone side surface of the luminous structure. The means for reflectinglight can also function to conduct heat away from the luminousstructure.

Another embodiment of the present invention is directed to a thirdgeneral luminous device. This device includes: a luminous structurehaving a light-emitting first surface, a second surface, at least oneside surface inclined at an angle compared to the second surface, anactive layer having a first surface and a second surface, a firstcladding layer on the first surface of the active layer and providingthe first surface of the luminous structure, a second cladding layer ona second surface of the active layer and providing the second surface ofthe luminous structure, and at least one groove separating at least thesecond cladding layer and the active layer while provide at least acontinuous portion of the first cladding layer, wherein one portion ofthe groove defines a major portion of the luminous structure and anotherportion of the groove defines a minor portion of the luminous structure;an insulation layer on at least a portion of the at least one sidesurface and the second surface of the luminous structure, wherein theinsulating layer includes a recess exposing at least a portion of thesecond cladding layer of the major portion of the luminous structure; apatterned first electrode layer in the recess and on at least a portionof the insulation layer, wherein the first electrode layer isdiscontinuous in the groove region; an insulated through via contactextending from the first electrode layer to the first cladding layer ofthe minor portion of the luminous structure; a conductive substrateattached to the first electrode, wherein the conductive substratecomprises a patterned conductive intermediate layer having a firstportion for attachment to the surface of the first electrode layercorresponding to the recess, and a second portion for electricalcommunication with the through via contact.

In another embodiment, the third general luminous device can include aconductive substrate comprising (i) a zener diode having first dopedregion and (ii) a second doped region extending through the secondconductive substrate, wherein the first portion of the patternedconductive intermediate layer is disposed on and within the first dopedregion of the conductive substrate and attached to at least a portion ofthe surface of the first electrode layer corresponding to the recess,and wherein the second portion of the patterned conductive intermediatelayer is disposed on the second doped region of the conductive substrateand contacting the through via contact of the minor portion of theluminous structure.

In still another embodiment, the third general luminous device caninclude a conductive substrate comprising (i) a zener diode having afirst doped region, a (ii) an insulated through via contact extendingthrough the second conductive substrate, wherein the first portion ofthe patterned conductive intermediate layer is disposed on the firstdoped region of the conductive substrate and attached to at least aportion of the surface of the first electrode layer corresponding to therecess, and wherein the second portion of the patterned conductiveintermediate layer is disposed on the through via contact of theconductive substrate and contacting the through via contact of the minorportion of the luminous structure.

Another embodiment of the present invention is directed to a firstgeneral luminous package including any of the previously describedluminous devices. In this embodiment, the luminous package includes: asubmount comprising a first conductive region and a second conductiveregion; a luminous device disposed on the first conductive region of thesubmount, the luminous device comprising, a luminous structure having alight emitting first surface, a second surface, at least one sidesurface inclined at an angle compared to the second surface, an activelayer having a first surface and a second surface, a first claddinglayer on the first surface of the active layer and providing the firstsurface of the luminous structure, and a second cladding layer on thesecond surface of the active layer and providing the second surface ofthe luminous structure; an insulation layer on at least a portion of theat least one side surface and the second surface of the luminousstructure, wherein the insulating layer includes a recess exposing atleast a portion of the second cladding layer; first and secondelectrodes connected to the luminous structure, wherein the firstelectrode is in the recess and on at least a majority of the insulationlayer; and a conductive substrate attached to at least a portion of asurface of the first electrode and the first conductive region of thesubmount; a first wire connecting the second electrode of the luminousdevice and the second conductive region of the submount. Any of thepreviously described luminous devices (and their variations) can be usedin the first general package claim.

In another embodiment, the first general luminous package includes asubmount further having a third conductive region, a fourth conductiveregion, at least one first through via connecting the connecting thefirst conductive region and the third conductive region, and at leastone second through via connect the second conductive region and thefourth conductive region.

In another embodiment, the first general luminous package (including allof the previously described embodiments of luminous devices) can includea luminous device having a conductive substrate with a zener diodecomprising an undoped region and a doped region of the conductivesubstrate, wherein the doped region has a conductive type opposite tothe conductive type of the second conductive substrate, and wherein onlythe doped region is in electrical communication with the firstelectrode; wherein the second conductive substrate further comprises apatterned conductive intermediate layer including a first portion formedon and within the doped region of the conductive substrate, and whereinat least a portion of the surface of the first electrode layer is boundto the first portion of the conductive intermediate layer to provideelectrical communication between the first electrode layer and the firstportion of the intermediate layer; and wherein the first wireelectrically connects the second electrode of the luminous device to thefirst conductive region of the submount, and a second wire electricallyconnects the conductive intermediate layer with the second conductiveregion of the submount.

Another embodiment of the present invention is directed to a secondgeneral luminous package including a luminous device. In thisembodiment, the luminous package includes: a submount comprising a firstconductive region and a second conductive region; a luminous devicedisposed on the first conductive region of the submount, the luminousdevice comprising, a luminous structure having a first surface, at leastone side surface, and a second surface, wherein the at least one side isinclined at an angle compared to the second surface, the luminousstructure comprising an active layer having a first side surface and asecond side surface, a first cladding layer on the first side surface ofthe active layer and providing the first surface of the luminousstructure, and a second cladding layer on a second side surface of theactive layer and providing the second surface of the luminous structure,and at least one groove separating at least the second cladding layerand the active layer while provide at least a continuous portion of thefirst cladding layer, wherein one portion of the groove defines a majorportion of the luminous structure and another portion of the groovedefines a minor portion of the luminous structure, an insulation layerformed on at least a portion of the at least one side surface and thesecond surface of the luminous structure, wherein the insulating layerincludes a recess to expose at least a portion of the second claddinglayer, a patterned first electrode layer formed in the recess and on atleast a portion of the insulation layer, wherein the first electrodelayer is discontinuous in the groove region, a through via contactextending from the first electrode layer to the first cladding layer ofthe minor portion of the luminous structure, and a conductive substrateattached to at least a portion of a surface of the first electrode, theconductive substrate comprising a patterned conductive intermediatelayer and a first doped region, wherein the patterned conductiveintermediate layer has a first portion positioned to be attached to atleast a portion of the surface of the first electrode layercorresponding to the recess, and a second portion positioned to be inelectrical communication with the through via contact of the minorportion of the luminous structure, and wherein the first doped regionhas a conductive type opposite to the conductive type of the secondconductive substrate, and is position to be in electrical communicationwith the through via contact of the minor portion of the luminousstructure and first conductive region of the submount; and a wireelectrically connecting the first portion of the conductive intermediatelayer to the second conductive region of the submount.

In another embodiment, the second general luminous package includes aluminous device having a the second conductive substrate including athrough via contact instead of the first doped region, wherein thethrough via contact extends through the second conductive substrate, andis positioned to be in electrical communication with the first portionof the patterned conductive intermediate layer, the through via contactof the minor portion of the luminous structure, and the first conductiveregion of the submount.

In another embodiment, any of the packages described herein can furtherinclude an encapsulant covering the luminous device, or at least onephosphor, or a combination thereof.

Another embodiment of the present invention is directed to luminoussystems including any of the luminous packages described herein. Thesepackages can also be formed into arrays.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other advantages of the present invention will becomereadily apparent by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings in which:

FIGS. 1A-1H illustrate one embodiment of a method for fabricating aluminous device;

FIG. 2A illustrates one method of processing a plurality of firstsubstrates;

FIG. 2B illustrates certain attributes of various materials useful informing the p-n junction of LEDs;

FIGS. 3 and 4 illustrate two embodiments of a luminous device, which canbe obtained from the method illustrated by FIGS. 1A-1H;

FIG. 5 illustrates a cross-sectional view of the embodiments illustratedin FIGS. 3 and 4;

FIGS. 6A-6C illustrate another embodiment of a method for fabricating aluminous device;

FIGS. 7, 9, and 10 illustrate three embodiments of a luminous device,which can be obtained from the method illustrated by FIGS. 6A-6C;

FIG. 8 illustrates a cross-sectional view of the embodiment illustratedin FIG. 7;

FIGS. 11A-11D illustrate another embodiment of a method for fabricatinga luminous device;

FIG. 11E illustrates a variation of the method illustrated in FIGS.11A-11D;

FIGS. 12 and 14 illustrate two embodiments of a luminous device, whichcan be obtained from the method illustrated by FIGS. 11A-11D;

FIG. 13 illustrates another embodiment of a luminous device, which canbe obtained from the method illustrated by FIG. 11E;

FIG. 15 is a circuit diagram illustrating a luminous device having azener diode;

FIGS. 16A and 16B illustrate two embodiments of a luminous device havinga zener diode;

FIG. 17 illustrates an embodiment of a luminous package;

FIG. 18 illustrates a cross-sectional view of the embodiment illustratedin FIG. 17;

FIGS. 19 and 20 illustrate two embodiments of luminous packages having azener diode;

FIGS. 21A and 21B illustrate two additional embodiments of luminouspackages having a zener diode;

FIG. 22 illustrate another embodiment of a luminous package;

FIGS. 23A-23D illustrate additional embodiments of luminous packages;

FIGS. 24-26 illustrate various embodiments of an array of luminouspackages; and

FIGS. 27-31 illustrate various embodiments of systems having one or moreluminous packages or arrays of luminous packages.

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will be described with reference tothe accompanying drawings. The present invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein. Rather, the embodiments areprovided so that disclosure of the present invention will be thoroughand complete, and will fully convey the scope of the present inventionto those skilled in the art. The principles and features of thisinvention may be employed in varied and numerous embodiments withoutdeparting from the scope of the present invention. In the drawings, therelative sizes of layers and regions may be exaggerated for clarity. Thedrawings are not to scale. Unless otherwise indicated, like referencenumerals designate like elements throughout the drawings.

As used herein, the phrase “patterning process” or “patterned element”(where the “element” can be a particular layer, region, or element)means forming a predetermined pattern of the layer, region or element.Such a predetermined pattern can be obtained, for example, by using anycombination of the following steps: at least one deposition step; atleast one photomasking step; at least one etching step; and/or at leastone photomask removing step. Two examples of a patterning processinclude the following combination of steps: (i) a deposition step, thena photomasking step, then an etching step, and then a photomask removingstep; or (ii) a photomasking step, then a deposition step, and then aphotomask removing step. In another example, the phrase “deposition andpatterning” means a patterning process including at least a depositionstep, a photomasking step, an etching step, and a photomask removingstep. Multiple masking, deposition, and/or etching steps can be used toobtain the desired pattern of the particular layer, region, or element.Nonlimiting examples of deposition methods include PVD, CVD (includingALD), plating (e.g., electroplating and electroless plating), andcoating (e.g., spin coating and spray coating).

As used herein, the term “luminous” means light emitting. For example,the phrase luminous device means a light emitting device. Nonlimitingexamples of luminous devices include a light emitting diode (“LED”) anda laser. Although all of the embodiments herein are described in view ofan LED, all of the embodiments can be converted to a laser, e.g., an LEDhaving a reflective first electrode and a semi-transparent mirror layer(also known as an output coupler) to the light emitting surface.

As used herein, when an element or layer is referred to as being “on,”“connected to” and/or “coupled to” another element or layer, the elementor layer may be directly on, connected and/or coupled to the otherelement or layer or intervening elements or layers may be present. Incontrast, when an element is referred to as being “directly on,”“directly connected to” and/or “directly coupled to” another element orlayer, no intervening elements or layers are present. As used herein,the term “and/or” may include any and all combinations of one or more ofthe associated listed items.

Furthermore, although the terms first, second, etc. may be used hereinto describe various elements, components, regions, layers and/orsections, these elements, components, regions, layers and/or sectionsshould not be limited by these terms. These terms may be used todistinguish one element, component, region, layer and/or section fromanother element, component, region, layer and/or section. For example, afirst element, component, region, layer and/or section discussed belowcould be termed a second element, component, region, layer and/orsection without departing from the teachings of the present invention.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like may be used to describe an element and/or feature'srelationship to another element(s) and/or feature(s) as, for example,illustrated in the figures. It will be understood that the spatiallyrelative terms are intended to encompass different orientations of thedevice in use and/or operation in addition to the orientation depictedin the figures. For example, when the device in the figures is turnedover, elements described as “below” and/or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.The device may be otherwise oriented (e.g., rotated 90 degrees or atother orientations) and the spatially relative descriptors used hereininterpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to limit the invention. As usedherein, the singular terms “a,” “an” and “the” are intended to includethe plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “includes”and/or “including”, when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence and/or addition ofone or more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein may have the same meaning as what is commonlyunderstood by one of ordinary skill in the art. It will be furtherunderstood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of this specification andthe relevant art and will not be interpreted in an idealized and/oroverly formal sense unless expressly so defined herein.

Embodiments of the present invention are described with reference tocross-section illustrations that are schematic illustrations ofidealized embodiments of the present invention. As such, variations fromthe shapes of the illustrations as a result, for example, ofmanufacturing techniques and/or tolerances, are to be expected. Thus,embodiments of the present invention should not be construed as limitedto the particular shapes of regions illustrated herein but are toinclude deviations in shapes that result, for example, frommanufacturing. For example, a region illustrated as a rectangle will,typically, have rounded or curved features. Thus, the regionsillustrated in the figures are schematic in nature of a device and arenot intended to limit the scope of the present invention.

The embodiments provided hereinafter generally provide luminous deviceshaving a conductive substrate. These luminous devices can be capable of(i) emitting light primarily towards at least one predetermineddirection, or (ii) substantially increasing the emission of reflectedlight, (iii) thermally conducting heat away from the luminous device, orany combination thereof.

One embodiment of the present invention is directed to a method ofmanufacturing a vertical-type luminous device using high throughputprocesses. FIGS. 1A-1H are cross-sectional views illustrating the methodfor a single luminous device. As is well understood by the skilledartisan, a plurality of luminous devices can be manufactured together ona single substrate, and multiple substrates can be manufactured at onetime, as illustrated in FIG. 2.

The method can utilize a pre-formed, multilayered, light-emittingheterostructure, as illustrated in FIG. 1A. The preformedheterostructure can be obtained according to desired specifications ormanufactured. Examples of useful manufacturing processes for theheterostructures can be found in U.S. Pat. No. 5,777,350 issued toNakmura et al. and titled “Nitride Semiconductor Light-Emitting Device,”U.S. Pat. No. 6,040,588 issued to Koide et al. and titled “SemiconductorLight-Emitting Device,” U.S. Pat. No. 5,959,307 issued to Nakamura etal. and titled “Nitride Semiconductor Device,” U.S. Pat. No. 5,753,939issued to Sassa et al. and titled “Light-Emitting Semiconductor DeviceUsing a Group III Nitride Compound and Having a Contact Layer Upon Whichan Electrode is Formed,” U.S. Pat. No. 6,172,382 issued to Nagahama etal. and titled “Nitride Semiconductor Light-Emitting and Light-ReceivingDevices,” and U.S. Pat. No. 7,112,456 issued to Park et al. and titled“Vertical GAN Light Emitting Diode and Method for Manufacturing theSame,” each of which patents are incorporated herein by reference intheir entirety. The preformed heterostructure typically includes atleast a first substrate 100, a first cladding layer 112 a, an activelayer 114 a, and a second cladding layer 116 a.

The first substrate 100 is typically a dielectric or a semiconductor.Examples of useful materials for the first substrate 100 include, butare not limited to, sapphire (Al₂O₃), ZnO, Si, SiC, GaAs, GaP, mixturesthereof, and alloys thereof. It is preferred to utilize a substrate thatis a good lattice match with the first cladding layer 112 a.

The first cladding layer 112 a, the second cladding layer 116 a, and theactive layer 114 a typically include a form of GaN or InGaN, which canbe expressed by the chemical formula In_(x)Al_(y)Ga_((1-x-y))N, where0≦x≦1 and 0≦y≦1. Accordingly, useful materials include, but are notlimited to, AlGaN and InGaN. Other useful materials are illustrated inFIG. 2B. The cladding layers and the active layer can also be doped withvarious materials. For example, the first cladding layer 112 a can be aSi doped n-type InGaN and the second cladding layer 116 a can be a Mgdoped p-type InGaN. Furthermore, the first cladding layer 112 a and thesecond cladding layer 116 a typically have opposite conductive types,and the conductivity types of the layers can be switched. For example,if the first cladding layer is n-type, the second cladding layer isp-type, and vice versa. For purposes of this embodiment, the firstcladding layer 112 a will be designated as n-type and the secondcladding layer 116 a will be designated as p-type.

The active layer 114 a produces light by recombining an electron and ahole in a p-n junction. The frequency (or wavelength) of light emitted,and, therefore, its color, depends on the band gap energy of thematerials forming the p-n junction and can be infrared, visible, orultraviolet. The active layer includes at least one potential well andpotential barrier, which form a Single Quantum Well. The active layercan also include a plurality of quantum wells to provide a MultipleQuantum Well. Light emitting characteristics can be adjusted by dopingthe potential barrier with a compound selected from the group consistingof B, Al, P, Si, Mg, Zn, Mn, Se, or a combination thereof. Preferreddoping materials include Al, Si, or a combination thereof.

The first cladding layer 112 a, the active layer 114 a, and the secondcladding layer 116 a can be sequentially formed on the first substrate100 by any process known to the skilled artisan. For example, theselayers can be formed on the substrate by MOCVD (metal organic chemicalvapor deposition), liquid phase epitaxial growth, hydride vapor phaseepitaxial growth, molecular beam epitaxial growth and/or metal organicvapor phase epitaxial growth. Thereafter, a heat treatment process canbe performed to activate the p-type cladding layer. Typical heattreatment temperatures are at about 400° C. to about 800° C. Forexample, if the second cladding layer 116 a is In_(x)Al_(y)Ga_((1-x-y))Ndoped with Mg, it is believed that the hydrogen associated with the Mgcan be removed to provide better p-type characteristics. The resultingheterojunction (e.g., the p-n junctions regions formed by the first andsecond cladding layers in or near the active layer) provides for highinjection efficiency at room temperature.

The multilayered, light-emitting hetero structure, illustrated in FIG.1A, is subjected to a patterning process to form a luminous structure110 having at least on side wall 113 and a top surface 115, asillustrated in FIG. 1B. The patterning process can include one or moremasking and etching steps. It is preferable to pattern the luminousstructure to have a shape which increases light emitting efficiency,e.g., by improving (i) internal reflections of photons, (ii) the escapeangle/path of the photons after reflectance, or (iii) both. For example,at least one side wall surface 113 of the luminous structure illustratedin FIG. 1B is angled to improve light reflectance and emission. Inparticular, it is preferred to form an angle α between an imaginary linecoinciding with the top surface 115 and the side wall surface 113, asillustrated in FIG. 1B, such that the surface area of the top surface115 is less than the surface area of the active layer 114. The angle αis preferably greater than about 30° but less than or equal to 90°, andmore preferably between about 40° to about 70°. The angle α can beconstant or vary continuously to form either partially or wholly concaveor convex sidewall shapes. Further nonlimiting examples of patternedshapes for the luminous structure 110 include an inverted parabola, aninverted truncated parabola, a frustum of a cone (i.e., truncated cone),a frustum of a pyramid (i.e., truncated pyramid), and a combinationthereof.

After forming the luminous structure, an insulating layer 120 (e.g., toprovide electrical insulation) is formed on the luminous structure 110,as illustrated in FIG. 1C. The insulating layer 120 can be conformallyformed on the luminous structure 110 so as to prevent electrical shortsbetween the p-type and n-type regions via the first electrode 140,described hereinafter. The insulating layer 120 is also believed toprovide additional structural support for the luminous structure 110.Insulating layer 120 is also preferably thermally conductive (e.g., bychoice of materials or by utilizing a very thin layer) so that heat canbe transferred to the first electrode layer 140 and away from theluminous structure 110. The insulating layer is also preferablytransparent, e.g., translucent enough to allow light to pass through itand be reflected by the later formed first electrode, describedhereinafter. The transparency of the material used in the insulatinglayer will also depend on the thickness of the layer, e.g., a thinnerlayer will be more transparent, and the wavelength of the emitted light.Accordingly, the thickness of the insulating layer 120 is preferablyfrom about 10 Å to about 1 um, and more preferably from about 1000 Å toabout 3000 Å, and wherein the thickness can be constant or varydepending on manufacturing processes and variations therein. It shouldbe noted that step coverage of the inclined sidewall surface 113. Usefulmaterials for the insulating layer include, but are not limited to,SiO₂, SiN_(x), ZnO, Al₂O₃, AlN, and combination thereof.

The insulating layer 120 can be formed by any method known in the art.In one example, the insulating layer 120 can be formed in a two stepprocess. The first insulating layer, such as SiO₂, can be utilized to asa gap filler. Then a second insulating layer having a higher etchselectivity than the first insulating layer can be formed on the firstinsulating layer. Thereafter, a patterning and etch process can beutilized to form a desired thickness and shape of the insulating layer120.

Alternatively, the insulating layer 120 can be formed in any manner toprevent electrical shorts between the p-type and n-type regions via thefirst electrode 140, discussed hereinafter. For example, in analternative embodiment, the insulating layer 120 can be formed to coveronly the first cladding layer 112 and the exposed side surfaces ofactive layer 114, e.g., by forming a patterned insulating layer. Instill another alternative embodiment, the insulating layer 120 can beformed to cover only the portions on which the later formed firstelectrode will be formed. For example, a patterned insulating layer 120can be formed only on the second cladding layer 116 and the exposed sidesurfaces of the active layer 114, when a patterned first electrode 140is formed on the patterned insulating layer. In still anotheralternative, the process step of forming the insulating layer can beskipped, if a patterned first electrode 140 (described hereinafter) isformed only on the second cladding layer 115. In this embodiment,electrical shorts are prevented because the first electrode 140 does notcontact either the active layer 114 or the first cladding layer. In thisembodiment, the patterned first electrode 140 can be formed utilizing aphotomask on the formed luminous structure 110 and then plating thefirst electrode 140.

The insulation layer is formed to include at least one recess 121, e.g.,by a patterning process, to expose a portion of the surface of thesecond cladding layer 116, thereby allowing electrical communicationbetween the second cladding layer 116 and the later formed firstelectrode 140, described hereinafter. Although FIG. 1C only illustratesone recess 121, more than one recess can be formed, and the recess canhave a variety of geometric shapes, e.g., a ring. Lastly, the recess 121can be formed anywhere along the top surface 115 of luminous structure110, along the one or more sidewall surfaces 113 of the luminousstructure 110 down to the active layer 114, or any combination thereof.Increasing the available surface area for electrical communicationbetween the second cladding layer 116 and the later formed firstelectrode 140 can be beneficial.

The insulating layer is preferably transparent, e.g., translucent enoughto allow light to pass through it and be reflected by the later formedfirst electrode, described hereinafter. The transparency of the materialused in the insulating layer will depend on the thickness of the layer,e.g., a thinner layer will be more transparent, and the wavelength ofthe emitted light. Useful materials for the insulating layer include,but are not limited to SiO₂, SiN_(x), ZnO, Al₂O₃, AlN, and combinationthereof.

After forming the insulating layer, a first electrode layer 140 isformed over the insulating layer 120 and in the recess 121 of theinsulating layer, as partially illustrated in FIG. 1D. It is believedthat, since the first electrode layer 140 can be in thermalcommunication with the second cladding layer surface 115 and at least aportion of at least one side wall surface 113 of the luminous structure110, the first electrode layer 140 can provide improved conduction ofheat away from the luminous structure.

Alternatively, when the insulating layer 120 is formed in a manner toprevent electrical shorts between the p-type and n-type regions via thefirst electrode 140, the first electrode layer 140 can be formed on theexposed portions of the second cladding layer 116 of the luminousstructure 110 and optionally also on any portion of the insulating layer120. For example, when a patterned insulating layer 120 is formed overonly the first cladding layer 112 and the exposed side surfaces ofactive layer 114, the first electrode 140 can be formed on the secondcladding layer 115 and optionally on any portion of the insulating layer120. Similarly, when a patterned insulating layer is formed only on thesecond cladding layer 116 and the exposed side surfaces of the activelayer 114, then a patterned first electrode 140 is formed on thepatterned insulating layer 120, e.g., the first electrode is not formedon the first cladding layer 112. These alternative embodiments alsoimprove heat conduction, since the first electrode 140 is in thermalcommunication with at least the second cladding layer surface 115 and atleast a portion of the at least one side surface 113 of the luminousstructure 110.

The first electrode layer 140 can be any electrically conductivematerial. Nonlimiting examples of useful materials include ITO(Indium-Tin-Oxide), Cu, Ni, Cr, Ag, Al, Au, Ti, Pt, V, W, Mo, mixturesthereof, and alloys thereof. It is preferred, however, to utilize areflective material for the first electrode layer 140 in order toreflect light through the insulation layer 120 and substantiallyincrease the light emitting efficiency. Examples of useful reflectivematerials include, but are not limited to Ag, Al, Pt or alloys thereofto increase the light emitting efficiency. Accordingly, the continuousfirst electrode layer 140 can serve either or both of the following twoadditional functions: (1) an electrical contact and (ii) a reflector oflight.

In an alternative embodiment, an ohmic layer 130 can be formed withinthe recess 121, e.g., by patterned deposition, before forming the firstelectrode layer 140, as illustrated in FIG. 1D. Useful materials for theohmic layer 130 include, but are not limited to ITO, ZnO, Ag, Cu, Ti, W,Al, Au, Pt, Ni, In₂O₃, SnO₂, Zn, mixtures thereof, and alloys thereof.Preferred materials for the ohmic layer include, but are not limited toZn, Ni, Ag, Ti, W, Pt, ITO, mixtures thereof and alloys thereof.Furthermore, a heat treatment can be performed to activate the ohmiclayer. Typically, the heat treatment can be conducted at about 400° C.before forming the first electrode layer.

Although not illustrated, additional layers can be added onto the firstelectrode layer. For example additional layers can be added to protectthe first electrode or provide additional structural strength toluminous structure 110.

After forming the first electrode layer 140, an optional process stepincludes patterning (e.g., a combination of a masking and etching steps)the areas 111 separating each luminous structure 110 to provideseparated luminous structures 110, as illustrated in FIG. 1E.Accordingly, in the areas 111 surrounding the luminous structure 110,the first electrode layer 140, the insulation layer 120, and the firstcladding layer 112 are removed to expose the first substrate 100. Thispatterning step, however, can be omitted or performed at a later time,e.g., after transfer to the second substrate or during separation of thesecond substrate. If patterning of the areas 111 around the luminousstructure 110 is conducted after transfer to the second substrate 200,the patterning will be conducted on the first cladding layer 112,resulting in a local removal of at least the first cladding layer 112.If patterning of the areas around the luminous structure 110 isconducted after transfer to the second substrate 200, it is alsopreferably to further locally remove the insulating layer 120, and thefirst electrode layer 140.

After forming the first electrode layer (assuming the step of patterningthe areas around the luminous structure is not conducted), at least aportion of the first electrode layer 140 (e.g., the outermost portionscorresponding to the top surface 115 of the luminous structure) isbonded to a second substrate 200, as illustrated in FIG. 1F. Any bondingmethod known in the art can be utilized. Nonlimiting examples of bondingmethods include eutectic bonding (e.g., using Au, Sn, Ag, Pb, mixturesthereof, and alloys thereof), soldering, gold-silicon bonding, andadhesive bonding. Also useful are conductive adhesive layers, asdescribed in U.S. Pat. No. 7,112,456 issued to Park et al. and titled“Vertical GAN Light Emitting Diode and Method for Manufacturing theSame,” which is incorporated herein by reference in its entirety.

The second substrate 200 is preferably conductive (typically p-typesilicon for an n-type first cladding layer) to allow electricalcommunication with the second cladding layer 116, e.g., via the firstelectrode and optionally the ohmic layer. Useful materials for thesecond substrate include, but are not limited to, Si, strained Si, Sialloy, Si—Al, SOI (silicon on insulator), SiC, SiGe, SiGeC, Ge, Gealloy, GaAs, InAs, Group III-V semiconductors, Group II-VIsemiconductors, combinations thereof, and alloys thereof.

As illustrated in FIG. 1F, the second substrate 200 can also include apatterned conductive intermediate layer 210 to enhance the bond betweenthe second substrate 200 and the first electrode layer 140, e.g.,compensate for the warpage in the first substrate and/or the secondsubstrate. The patterned conductive intermediate layer 210 is formed onsecond substrate 200 before bonding the second substrate 200 to at leasta portion of the first electrode layer 140 (e.g., the outermost portionscorresponding to the top surface 115 of the luminous structure) to thesecond substrate 200, as illustrated in FIG. 1F. The conductiveintermediate layer 210 is patterned to substantially align and matchwith the bonding surface (or surfaces) of the first electrode layer 140.The intermediate layer 210 (typically used for eutectic bonding) canhave lower reflective characteristics than the first electrode. Usefulmaterials for the intermediate layer 210 include, but are not limitedto, Au, Ag, Pt, Ni, Cu, Sn, Al, Pb, Cr, Ti, W, combinations thereof, andalloys thereof. For example, when Au—Sn is used as the intermediatelayer 210, bonding can be conducted via a thermal process (e.g., atabout 200° C. to about 400° C.) and optionally utilize pressure.Furthermore, the intermediate layer can be a single layer or multiplelayers, e.g., each layer having a different material or alloy.

Another optional additional process step is thinning the secondconductive substrate 200 to a desired thickness before removing thefirst substrate 100, because it is difficult to thin the secondconductive substrate after removing the first substrate 100. Forexample, the second conductive substrate can be thinned by a CMPprocess, a grinding process, an etching process, or any combinationthereof.

The transfer to the second substrate 200 is completed when the firstsubstrate 100 is removed to expose the first cladding region 112, asillustrated in FIG. 1G. The first substrate can be removed using anymethod know to the skilled artisan. For example, a laser can be utilizedto separate the first substrate, as provided in U.S. Pat. No. 7,112,456issued to Park et al. and titled “Vertical GaN Light Emitting Diode andMethod for Manufacturing the Same,” which is incorporated herein byreference in its entirety. If a laser is utilized, it is preferable tofirst thin and/or polish the first substrate 100 (e.g., by CMP,grinding, and/or etching) before utilizing the laser. In anotherexample, the first substrate 100 can be removed using a chemicalprocess, e.g., a chemical lift-off (CLO). An example of an appropriateCLO process is provided in Ha et al., “The Fabrication of VerticalLight-Emitting Diodes Using Chemical Lift-Off Process,” IEEE PhotonicsTechnology Letters, Vol. 20, No. 3, pp. 175-77 (Feb. 1, 2008), and U.S.Pat. No. 4,846,931 issued to Gmitter and titled “Method for Lifting-OffEpitaxial Films,” which are incorporated herein by reference in theirentirety.

After removing the first substrate, a second electrode 150 is formed onthe exposed first cladding region 112, as illustrated in FIG. 1H. Sincethe second electrode is preferably shaped to minimize interference withlight emission, the second electrode 150 typically has a substantiallysmaller surface area in comparison to the surface area of the firstcladding region 112. The second electrode can be formed using anyprocess know to the skilled artisan. For example, the second electrodecan be formed using (i) a deposition (e.g., CVD, sputtering, etc. of thesecond electrode material) and patterning process or (ii) a photo-resistlift off process.

The second electrode 150 can also have various configurations to improvecurrent spreading. For example, the second electrode can be formed (i)near at least one edge of the first cladding region, (ii) in the shapeof a frame formed on the edge of the first cladding region, and/or (iii)to include a plurality of smaller electrodes.

Useful materials for the second electrode 150 include, but are notlimited to, ITO (Indium-Tin-Oxide), Cu, Ni, Cr, Au, Ti, Pt, Al, V, W,Mo, Ag, mixtures thereof, and alloys thereof. The second electrode 150can be formed as a single layer or multiple layers, e.g., each layerhaving a different material or alloy. The second electrode 150 ispreferably made of a material that is at least semi-transparent.

In an alternative embodiment, an ohmic layer (not illustrated) can beformed between the surface of the first cladding layer 112 and thesecond electrode 150. Useful materials for the ohmic layer include, butare not limited to ITO, ZnO, Zn, Ti, Pt, Al, Ni, In₂O₃, SnO₂, mixturesthereof, and alloys thereof. Preferred materials for the ohmic layerinclude, but are not limited to ITO, Ti, Pt, Ni, mixtures thereof andalloys thereof. Furthermore, a heat treatment can be performed toactivate the ohmic layer. Typically, the heat treatment is conducted atabout 400° C. before forming the second electrode 150.

Although not illustrated in FIG. 1H, a conductive layer can also beadded to the surface of the first cladding layer in order to improvecurrent spreading, e.g., before attaching the second electrode 150. Thehereinbefore described ohmic layer can also serve as the conductivelayer. It is preferred to use a transparent conductive layer, such asITO (Indium-Tin-Oxide).

The exposed surface of the first cladding layer 112 can also be textured(not shown) before attaching the second electrode 150 to increase thelight emitting efficiency. Surface texturing can be applied to any ofthe embodiments described herein. In order to enhance the attachment ofthe second electrode 150 to the exposed surface of the first claddinglayer 112, the area of the first cladding layer 112 (where the electrode150 attaches) can be free from surface texturing. It is believed thatsurface texturing reduces the total internal reflection resulting fromthe difference in refractive index between the first cladding layer andair. Surface texturing can be done by any known process known to theskilled artisan. One example of such a process is the use of a wetetchant, such as KOH.

After the second electrode 150 is formed, the second substrate 200 andthe areas around the luminous structure can be separated to form atleast one luminous device 1 including at least one luminous structure110, as illustrated in FIG. 1H. Any process known to the skilled artisancan be used to separate the second substrate 200 and the areas aroundthe luminous structure. Nonlimiting examples of processes for separatingthe second substrate and the areas around the luminous structureinclude, but are not limited to, laser sawing, blade sawing, diamondcutting, etching, and combinations thereof.

The hereinbefore described “optional process step” of patterning theareas 111 around the luminous structure (e.g., as described hereinbeforein relation to FIG. 1E) can be conducted before or concurrently with theprocess step of separating the second substrate into individual luminousdevices, as illustrated in FIGS. 1G and 1H. For example, the areasaround the luminous structure can be patterned (e.g., a combination ofat least one masking and etching step) to locally remove the firstcladding layer 112, the insulating layer 120, and the first electrodelayer 140. Thereafter, the second substrate can be separated, e.g., bylaser sawing.

Another embodiment of the present invention is also directed to avertical-type luminous device formed on a conductive substrate. Such aluminous device can be manufactured according to the high throughputprocess described hereinbefore.

FIGS. 3-5 illustrates two embodiments of the vertical-type luminousdevice 1. FIG. 3 illustrates one embodiment having a substantiallysquare-shaped top profile, FIG. 4 illustrates another embodiment havinga substantially rectangular-shaped top profile, and FIG. 5 is across-sectional illustration of the embodiments illustrated in FIGS. 3and 4 along axis A-A. Although these embodiments are described inrelation to the shape of the top profile or the shape of the luminousstructure 110, these references are intended only as a reference to thetop profile or the overall shape of the luminous structure 110.Accordingly, the luminous devices described herein are not limited tothese shapes and can have any desired overall outer shape.

In the embodiments illustrated in FIGS. 3-5, the vertical-type luminousdevice 1 includes (i) a multilayered, light-emitting luminous structure110 having a first surface 109, a second surface 115, and at least oneside surface 113, (ii) an insulating layer 120 covering the secondsurface 115 and at least a portion of the at least one side surface 113of the luminous structure 110, (iii) first and second electrodes (140,150 respectively) connected to the luminous structure 110, and (iv) aconductive substrate 200 bound to the first electrode 140. The luminousdevice 1 can further include an intermediate layer 210 between the firstelectrode 140 and the conductive substrate 200 in order to enhance thebond, e.g., compensate for the warpage in the conductive substrate 200,and an ohmic region 130 situated to contact the second surface 115 ofthe luminous structure 110 and the first electrode 140, e.g., the ohmicregion can be placed in a recess within the insulating layer 120.

The multilayered, light-emitting luminous structure 110 includes a firstcladding layer 112, an active layer 114, and a second cladding layer116. The luminous structures of this embodiment are preferably shaped toincrease light emitting efficiency, e.g., by improving (i) internalreflection of light, (ii) the escape angle/path of the light afterreflectance, or (iii) both. For example, at least one side wall surface113 of the luminous structure illustrated in FIG. 5 can be angled toimprove light reflectance. In particular, it is preferred to form aninternal angle α between an imaginary line coinciding with the secondsurface 115 and the side wall surface 113, as illustrated in FIG. 5,such that the top surface area of the first surface 109 is greater thanthe top surface area of the active layer 114. The angle α is preferablygreater than about 30° but less than or equal to 90°, and morepreferably between about 40° to about 70°. The angle α can be constantor vary continuously to form either partially or wholly concave orconvex sidewall shapes. Further nonlimiting examples of shapes for theluminous structure 110 include a parabola, a truncated parabola, aninverted frustum of a cone (i.e., truncated cone), an inverted frustumof a pyramid (i.e., truncated pyramid), and a combination thereof. Forexample, FIGS. 3 and 4 respectively illustrate a luminous structure 110having the shape of an inverted frustum of a pyramid (e.g., having asubstantially square base) and a frustum of an elongated pyramid (e.g.,having a substantially rectangular base).

Furthermore, the exposed surface of the first cladding layer 112 can betextured (not shown), as hereinbefore described. Surface texturing canalso be prevented in selected areas, e.g., in areas where the secondelectrode 150 attaches to the exposed surface of the first claddinglayer 112.

The insulating layer prevents electrical shorts between the p-type andn-type regions via the first electrode 140, described hereinafter. It isbelieved that the insulating layer also provides additional structuralsupport for the luminous structure 110. Insulating layer 120 is alsopreferably thermally conductive (e.g., by choice of materials or byutilizing a very thin layer) so that heat can be transferred to thefirst electrode layer 140 and away from the luminous structure 110. Theinsulating layer is also preferably transparent, e.g., translucentenough to allow light to pass through it and be reflected by the laterformed first electrode, described hereinafter. The transparency of thematerial used in the insulating layer will also depend on the thicknessof the layer, e.g., a thinner layer will be more transparent, and thewavelength of the emitted light. Useful materials for the insulatinglayer include, but are not limited to SiO₂, SiN_(x), ZnO, Al₂O₃, AlN,and combination thereof.

As illustrated in FIG. 5, the insulating layer 120 can cover secondsurface 115 and the entire side surface 113 of the luminous structure110. In another embodiment, the insulating layer 120 can cover thesecond surface 115 and at least a portion of the at least one sidesurface 113 of the luminous structure 110, e.g., covers at least thesecond cladding layer 116 and the active layer 114. In anotherembodiment, the insulating layer 120 can cover only the first claddinglayer 112 and the exposed side surfaces of active layer 114, e.g., byforming a patterned insulating layer 120. In still another alternative,the insulating layer is optional and can be removed if the firstelectrode 140 only extends up the sides of the second cladding layer116, e.g., when the first electrode is not in electrical communicationwith the first cladding layer 112 or the active layer 114.

The insulating layer also includes at least one recess 121 exposing thesecond cladding layer 116 of the luminous structure 110 to allowelectrical communication through the insulating layer. Although notillustrated, one or more recesses 121 can be positioned (i) in anoff-centered location along second surface 115, (ii) along secondsurface 115 of luminous structure 110 and side surface 113 of luminousstructure 110 but below active layer 114, (iii) along one or more sidesurfaces 113 but below the active layer 114, or a combination thereof.These alternative locations for recess 121 can be useful to improvecurrent flow. The insulating layer 120 is preferably transparent, e.g.,translucent enough to allow at least some light to pass through it.

The first and second electrodes (140, 150 respectively) are inelectrical communication with the luminous structure 110. Morespecifically, the first electrode 140 is in electrical communicationwith second cladding layer 116 of the luminous structure 110, and thesecond electrode 150 is in electrical communication with the firstcladding layer 112 of the luminous structure 110.

Accordingly, the first electrode 140 is electrically isolated from theactive layer 114 and the first cladding layer 112. Electrical isolationof the first electrode 140 can be obtained by having the first electrodeextend along the side surface 113 but not reaching up to the activelayer 114 of the hetero structure, e.g., only along second surface 115or along second surface 115 and part of side surface 113 of the luminousstructure 110. Alternatively, electrical isolation can be obtained byutilizing an insulating layer, as illustrated in FIG. 5 and describedhereinbefore in the description of the insulating layer for thisembodiment and in the method of manufacturing section.

In the embodiment illustrated in FIG. 5, the first electrode 140 cancover any portion of the insulating layer as long as part of the firstelectrode is in electrical communication with the second cladding layer116 through recess 121 of insulating layer 120. For example, the firstelectrode 140 can cover substantially all of the insulating layer 120,as illustrated in FIG. 5. It is believed that the insulating layer andthe first electrode can provide further structural support to theluminous structure 110. Alternatively, when a patterned insulating layer120 covers only the first cladding layer 112 and the exposed sidesurfaces of active layer 114, the first electrode 140 can be formed onthe second cladding layer 115 and optionally on any portion of theinsulating layer 120. Similarly, when a patterned insulating layercovers only the second cladding layer 116 and the exposed side surfacesof the active layer 114, then a patterned first electrode 140 covers thepatterned insulating layer 120, e.g., the first electrode is not formedon the first cladding layer 112.

In regard to the second electrode 150, the size and shape are chosen tomaximize current flow while minimizing interference with light emittedfrom the luminous structure 110. Accordingly, the second electrode 150can have various configurations to improve current spreading and/ordecrease interference with emitted light. For example, the secondelectrode 150 can be formed (i) near at least one edge of the firstcladding layer 112, (ii) in the shape of a frame formed on the edge ofthe first cladding layer, (iii) to include a plurality of smallerelectrodes, or a combination thereof. Although not illustrated in FIG.1H, a conductive layer can also be added to the first surface 109 of thefirst cladding layer 112 in order to improve current spreading. It ispreferred to use a transparent conductive layer, such as ITO(Indium-Tin-Oxide).

The luminous device 1 further includes a conductive substrate 200 boundto at least a portion of the first electrode 140, thereby allowingelectrical communication with the second cladding layer 116. Any bondingmethod known in the art can be utilized. Nonlimiting examples of bondingmethods include eutectic bonding, soldering, gold-silicon bonding, andadhesive bonding. Also useful are conductive adhesive layers, asdescribed in U.S. Pat. No. 7,112,456 issued to Park et al. and titled“Vertical GAN Light Emitting Diode and Method for Manufacturing theSame,” which is incorporated herein by reference in its entirety.

The conductive substrate 200 can also include a conductive intermediatelayer 210 to enhance the bond with the first electrode 140, e.g.,compensate for the warpage in the first substrate and/or the secondsubstrate. The intermediate layer 210 (typically used for eutecticbonding) can have lower reflective characteristics than the firstelectrode. The intermediate layer can be a single layer or multiplelayers, e.g., each layer having a different material or alloy.

Further details (e.g., how to make and material constituents) about theluminous device 1 and its various parts (e.g., the luminous structure110, the first and second electrodes 140, 150, the conductive substrate200, etc.) can be found in the hereinbefore-described sections on themethod of manufacturing a luminous device.

As illustrated in FIG. 5, it is believed that the luminous device 1illustrated in FIG. 5 can significantly improve light emission,especially when a transparent insulation layer 120 and a reflectivefirst electrode 140 are utilized. In addition to light rays directlyemitted from the active area (e.g., light ray L1), the angled sidesurfaces 113 of the luminous device 1 allow at least once reflectedlight (e.g., light ray L2) and twice reflected light (e.g., light rayL3) to be emitted from the heterostructure. Accordingly, thedirectionality of the emitted light can be substantially controlledwhile substantially increasing the amount of total emitted light.Furthermore, it is believed that, since the first electrode layer 140 isin thermal communication with the second cladding layer surface 115 andat least a portion of at least one side wall surface 113 of the luminousstructure 110, the first electrode layer 140 can provide improvedconduction of heat away from the luminous structure 110 and into theconductive substrate 200. This cooling effect can be substantial, sincethe first electrode layer 140 also has a significant contact area withthe conductive substrate 200.

Another embodiment of the present invention is directed to a method ofmanufacturing a luminous device with the second electrode 150 (e.g., topelectrode) provided in a location that does not interfere with lightemitted from the heterostructure. Such a configuration can be obtainedby forming a grooved luminous structure, as illustrated by FIGS. 6A-6C.This method is a variation of the hereinbefore described method formanufacturing a vertical-type luminous device. Accordingly, the generalsteps of the method are essentially the same and equally applicable tothe present embodiment, except for specific changes described below. Forexample, the method of this embodiment also undergoes the followingprocess steps: (i) forming the luminous structure; (ii) forming theinsulation layer having a recess; (iii) forming the first electrode andoptional ohmic layer; (iv) optional patterning of the areas around theluminous structure (which can be conducted at a later time); (v) bondingthe first electrode surface to a second conductive substrate; (vi)removing the first substrate; (vii) forming a second electrode; and(viii) separating the second substrate into individual luminous devices.Similarly, all of the variations regarding the insulating layer 120 andthe first electrode 140 described hereinbefore for the earlierembodiments (e.g., relating to FIGS. 1A-1H, and FIGS. 3-5) equally applyto this embodiment.

In this embodiment, the pre-formed, multilayered, light-emittingheterostructure (illustrated in FIG. 1A) is subjected to a patterningprocess to form a luminous structure 110 having at least one groove 118separating at least the second cladding layer 116 and the active layer114 of the luminous structure 110, as illustrated in FIG. 6A. Oneportion of the groove defines side surface 113 b of a major portion 110a of the luminous structure 110, and another portion of the groovedefines side surface 117 of a minor portion 110 b of the luminousstructure 110. At least a portion of the first cladding layer 112,therefore, remains as a continuous layer to provide electricalcommunication between the minor portion 110 b and the major portion 110a of the luminous structure. Side surface 113 b and/or side surface 117can be angled as describe hereinbefore in relation to the embodimentillustrated in FIG. 5. In this embodiment, only the major portion 110 aof the luminous structure emits light. Although FIGS. 6A-6B illustrate astraight groove 118, the groove can also be curved.

As illustrated by FIGS. 6B and 6C, the remaining process steps of thisembodiment are essentially the same (except for the formation of thesecond electrode) as process steps in the hereinbefore described methodof manufacturing a luminous device, which method is incorporated hereinby reference in its entirety. For example, an insulating layer 120(including a recess 121) is formed to conform to the shape of theluminous structure, e.g., the insulating layer is also formed in groove118. The insulating layer 120 also includes a recess 121, which can beformed by a patterning process. Thereafter, a first electrode layer 140is formed on the insulating layer 120 (including the regioncorresponding to the groove) and in recess 121, as illustrated in FIG.6B. Alternatively, an ohmic layer 130 can be formed in recess 121, asalso illustrated in FIG. 6B. Thereafter, a second conductive substrate200 (which can optionally have a patterned conductive intermediate layer210) is bound to at least a portion of the first electrode layer 140,and the first substrate 100 is removed, as partially illustrated in FIG.6C. Furthermore, the conductive substrate 200 can also include apatterned intermediate layer 210 to enhance the bond between theconductive substrate 200 and the first electrode layer 140.

In contrast to the hereinbefore described method, however, the method ofthis embodiment forms the second electrode 150 on first cladding layer112 of the minor portion 110 b of the luminous structure, as illustratedin FIG. 6C. Accordingly, the second electrode 150 (disposed on the minorportion 110 b) does not interfere with light emitted from the majorportion 110 a of the luminous structure 100. Second electrode 150 can,therefore, be made of any conductive material suitable for firstcladding layer 112 (e.g., can be a transparent material, opaquematerial, or a non-transparent material), and the second electrode 150can extend across a portion or the entire surface of the first claddinglayer of the minor portion of the luminous structure 110 b.

Furthermore, although not illustrated in FIG. 6C, a conductive layer canalso be added to the surface of the first cladding layer 112 of themajor portion 110 a and optionally to the minor portion 100 b of theluminous structure 110 in order to improve current spreading, e.g.,before attaching the second electrode 150. It is preferred to use atransparent conductive layer, such as ITO (Indium-Tin-Oxide), since thisconductive layer will cover the light-emitting major portion 110 a ofthe luminous structure 110.

After forming the second electrode 150, the second substrate 200 and theareas around the luminous structure can be separated to form at leastone luminous device 2 including at least one luminous structure 110 asillustrated in FIG. 6C. Any process known to the skilled artisan can beused to separate the second substrate and the areas around the luminousstructure. Nonlimiting examples of processes for separating the secondsubstrate and the areas around the luminous structure include, but arenot limited to, laser sawing, blade sawing, diamond cutting, etching,and combinations thereof.

Another embodiment of the present invention is also directed to avertical-type luminous device formed on a conductive substrate, whereinthe top electrode does not interfere with light emitted primarilytowards at least one predetermined direction. Such a luminous device canbe manufactured according to the high throughput process describedhereinbefore for a luminous device having a grooved luminous structure.Accordingly, all of the details (e.g., materials, configuration, etc.)provided in the hereinbefore described process also applies to thisembodiment.

FIGS. 7 and 8 illustrate one embodiment of a luminous device 2 having amajor light-emitting portion 110 a and a minor portion 110 b forattaching the second electrode 150. As a result, the second electrode150 does not interfere with light emission. FIG. 8 is a cross-sectionalview of the luminous device 2 along axis B-B illustrated in FIG. 7. Asillustrated in FIGS. 7 and 8, the second electrode 150 is formed on asubstantially-rectangular (top profile) minor portion 110 b of theluminous conductive structure. A groove 118 defines a major portion 110a and a minor portion 110 b of the luminous structure 110. Accordingly,the portions of the luminous device 2 corresponding to the portions ofthe luminous structure 110 will be respectively referred to as the“major portion of the luminous device” and the “minor portion of theluminous device.”

The groove 118 separates at least the active layer 114 and the secondcladding layer 120 (and optional a part of the first cladding layer 112)of the luminous structure 110. As a result, at least a part of the firstcladding layer 112 is continuous throughout the luminous structure 110.Since the second electrode 150 is attached to the first cladding layer112 in the minor portion of the luminous device 2, electricity will flowalong the continuous first cladding layer 112 (or along its surface) anddistribute within the major portion of the luminous device 2, wherelight will be produced.

Except for the absence of second electrode 150, the major portion of theluminous device 2 (corresponding to the major portion 110 a) issubstantially similar to luminous device 1 illustrated in FIG. 5.Accordingly, all of the detail and variations of luminous device 1 applyequal to the major portion of the luminous device 2. For example, themajor portion of the luminous device 2 includes (i) a multilayered,light-emitting luminous structure 110 having a first surface 109, asecond surface 115, and at least one side surface 113 a (or side surface113 b forming part of the groove 118), (ii) an insulating layer 120having a recess 121 and covering the second surface 115 and at leastportion of the sides 113 a, 113 b of the luminous structure, (iii) afirst electrode 140 connected to the major portion of the luminousstructure 110, and (iv) a conductive substrate 200 bound to the firstelectrode 140. The major portion of the luminous device 2 can furtherinclude an ohmic region 130 situated to contact the second surface 115of the luminous structure 110 and the second electrode 140, e.g., theohmic region 130 can be placed in a recess within insulating layer 120.The luminous device 2 can further include an intermediate layer 210 toenhance the bond, e.g., compensate for the warpage in the conductivesubstrate 200.

Furthermore, the exposed surface of the first cladding layer 112 of themajor portion 110 a can also be textured (not shown) before attachingthe second electrode 150 on first cladding layer 112 of the minorportion 110 b of the luminous structure to increase the light emittingefficiency. In order to enhance the attachment of the second electrode150 to the exposed surface of the first cladding layer 112 of the minorportion 110 b, the area of the first cladding layer 112 of the minorportion 110 b where the second electrode 150 attaches can be free oftexturing. It is believed that surface texturing reduces the totalinternal reflection resulting from the difference in refractive indexbetween the first cladding layer 112 of the major portion 110 a and air.Surface texturing can be done by any known process known to the skilledartisan. One example of such a process is the use of a wet etchant, suchas KOH.

As illustrated in FIG. 8, the minor portion 110 b of the luminous device2 includes a second electrode 150 in electrical communication with thefirst cladding layer 112. The second electrode 150 can extend across aportion or the entire surface of the first cladding layer of the minorportion of the luminous structure 110 b. For example, the secondelectrode can have a crescent shape to enhance current distribution.Accordingly, the minor portion 110 b of the luminous device 2 alsoincludes an insulation layer 120 and optionally the first electrodelayer 140. Although the minor portion of the luminous device 2 does notrequire a first electrode layer 140, it may be more convenient toinclude it during high throughput processing.

It is believed that the luminous device 2 illustrated in FIGS. 7 and 8can significantly improve light emission with the second electrode 150placed in a non-interfering position, and especially when a transparentinsulation layer 120 and a reflective first electrode 140 are utilized.In addition to light rays directly emitted from the active area (e.g.,light ray L1), the angled side surfaces 113 of the luminous device 1allow at least once reflected light (e.g., light ray L2) and twicereflected light (e.g., light ray L3) to be emitted from the heterostructure. Accordingly, the directionality of the emitted light can besubstantially controlled while substantially increasing the amount oftotal emitted light. Furthermore, it is believed that, since the firstelectrode layer 140 is in thermal communication with the second claddinglayer surface 115 and at least a portion of at least one side wallsurface 113 of the major portion 110 a of the luminous structure 110,the first electrode layer 140 can provide improved conduction of heataway from the luminous structure 110 and into the conductive substrate200. This cooling effect can be substantial, since the first electrodelayer 140 also has a significant contact area with the conductivesubstrate 200.

In an alternative embodiment, the hereinbefore described process formanufacturing the grooved luminous structure can be modified tomanufacture a luminous device 3 having a second electrode 150 formed ona substantially-square (top profile), minor portion 110 b of theluminous structure 110 (e.g., defined by two grooves 118) in a cornerquadrant, as illustrated in FIG. 9. Accordingly, when viewed from a topprofile, the substantially-square minor portion 110 b is formed at onecorner quadrant of a luminous device having a square shaped top profile.In another variation of this embodiment, luminous device 3 can have morethan one substantially-square minor portions (not shown), e.g., one onopposite corner quadrants, or one on each corner quadrant. In thesealternative embodiments, the preformed, multilayered, light emittingheterostructure can be patterned to form a luminous structure having aplurality of grooves.

In another alternative embodiment, a luminous device 4 can include aminor portion 110 b of the luminous structure formed in a centrallocation of the luminous structure 110, as seen from a top profile andillustrated in FIG. 10. In this embodiment, four grooves in a squareformation (or a single groove in a circular formation) can be utilizedto form the minor portion 110 b as an island in a central location ofthe luminous structure 110. Since the second electrode 150 is formed onthe minor portion 110 b, its central location can help to increasecurrent distribution outward in a radial direction from the center tothe outer light emitting major portion 110 a of the luminous structure110. In this embodiment, the insulating layer has a recess (andoptionally an ohmic layer) having a substantially square shapecorresponding to the shape of the major portion.

Although all of the shapes referenced hereinbefore are square orrectangular, other shapes are also possible for any part of the luminousdevices described hereinbefore. For example, the minor portions of theluminous structure can have a circular or oval top profile shape. Inthis example, a single groove will have a circular or oval shape.

In another embodiment, the present invention is directed to a method ofmanufacturing a vertical-type luminous device having a lens, asillustrated in FIGS. 11A-11D. This method is a variation of thehereinbefore described methods for manufacturing a vertical-typeluminous device and a vertical-type luminous device having a groove. Inthis embodiment, a portion of the first cladding layer is utilized toform the lens. It is believed that the curvature of the lens increasesthe light emitting efficiency by reducing the escape cone angle, whichis a phenomena resulting from the difference in refractive indexesbetween the first cladding layer and air.

In this embodiment, the method utilizes a pre-formed, multilayered,light-emitting heterostructure, as illustrated in FIG. 11A. Similar tothe preformed heterostructure described in relation to FIG. 1A, thepreformed heterostructure of this embodiment illustrated in FIG. 11Aincludes at least a first substrate 100, a first cladding layer 111 a,an active layer 114 a, and a second cladding layer 116 a. However, thepreformed heterostructure in this embodiment has a first cladding layer111 a that is substantially thicker to compensate for the lens portion.In this embodiment, the thickness of the first cladding layer 111 a istypically greater than about one tenth the length of the shortest side(or shortest diameter) of the first surface 109 of the luminousstructure 110 on which the lens will be formed, when viewed from a topprofile. In the hereinbefore described grooved luminous devices, onlythe first surface 109 of the major portion 110 a is relevant fordetermining the shortest side (or shortest diameter). Such a thick firstcladding layer 111 a can be obtained by any method known to the skilledartisan, such as vapor phase epitaxy.

The other process steps are essentially the same as the process steps ofthe hereinbefore described methods for manufacturing a vertical-typeluminous device and a vertical-type luminous device having a groove. Forexample, the method of this embodiment also undergoes the followingprocess steps: (i) forming the luminous structure; (ii) forming theinsulation layer having a recess; (iii) forming the first electrode andoptional ohmic layer; (iv) optional patterning of the areas around theluminous structure (which can be conducted at a later time); (v) bondingthe first electrode surface to a second conductive substrate; (vi)removing the first substrate; (vii) forming a second electrode; and(viii) separating the second substrate into individual luminous devices.

However, in this embodiment, the method further includes an additionalstep of forming a lens 119 from the first cladding layer 111, asillustrated in FIG. 11C. After the process step of removing the firstsubstrate, the first cladding layer 111 is exposed, as illustrated inFIG. 11B. Thereafter, a patterning process is conducted on the firstcladding layer 111 using a shaped photo resist pattern to form the lens119 from the first cladding layer 111 and define the areas around thelens, as illustrated in FIGS. 11B and 11C. An example of a patternprocess to form the lens is described in Stern et al., “Dry etching forcoherent refractive microlens arrays,” Optical Engineering, Vol. 33, No.11, p. 3547-51 (November 1994), and U.S. Pat. No. 5,948,281, issued toOkazaki et al. on Sep. 7, 1999 and titled “Microlens array and method offorming same and solid-state image pickup device and method ofmanufacturing same,” which are incorporated herein by reference in itsentirety.

Although FIGS. 11A-11D illustrate a convex lens, the first claddinglayer 111 can be shaped into any desirable shape to obtain the desiredlight emitting pattern. For example, in a variation of the above processstep, a plurality of lenses 119 can be obtained by altering the lensshaping pattern to provide a plurality of smaller lenses, as illustratedin FIG. 11E.

After forming the at least one lens, the second electrode 150 is formedon the lens (or a plurality of lens) made from the first cladding layer111, as illustrated in FIG. 11D and as previously describedhereinbefore. In embodiments where the luminous device has a groove, thesecond electrode 150 can be formed on the first cladding layer 111 ofthe minor portion of the luminous device.

The present invention is also directed to a vertical-type luminousdevice formed on a conductive substrate, wherein the luminous deviceincludes a lens. Any of the previously described embodiments can includea lens as herein described. Such a luminous device can be manufacturedaccording to the high throughput process described hereinbefore for aluminous device having a lens.

FIGS. 12-14 illustrate three variations of a vertical-type luminousdevice having a lens formed from the first cladding layer 111. FIGS. 12and 13 respectively illustrate luminous devices having one large lensand a plurality of smaller lenses. In FIG. 12, the luminous device 5comprises a luminous structure having a single lens 119, wherein thesecond electrode 150 is bound to the lens. In FIG. 13, the luminousdevice 6 comprises a luminous structure having a plurality of lenses119, wherein the second electrode 150 is bond to a group ofcentrally-located small lenses. Alternatively, the area where the secondelectrode is bound can be flat, e.g., devoid of lenses. These luminousstructures further include a first electrode 140 which is bound to aconductive substrate 200. The conductive substrate 200 can furtherinclude an intermediate layer 210 to enhance the bound, e.g., compensatefor warpage in the conductive substrate 200.

Similarly, FIG. 14 illustrates a luminous device 7 having a groove 118,which defines a major portion 110 a and a minor portion 110 b of theluminous device. The major portion of the luminous device includes alens 119, and the minor portion of the luminous device includes thesecond electrode 150. As discussed hereinbefore, in this embodiment, thesecond electrode 150 does not interfere with light emitted from themajor portion of the luminous device. Accordingly, the second electrode150 can be made from any desired conductive material, and it can takeany shape, e.g., the second electrode 150 can cover the entire surfaceof the first cladding layer in the minor portion of the luminous device.Although not illustrated in FIG. 13, the luminous device 7 can furtherinclude a current spreading layer on the surface of the first claddinglayer and optionally the surface of the lens 119.

In another embodiment, the present invention is directed to a method ofmanufacturing a vertical-type luminous device having an embedded zenerdiode within the conductive substrate 200. Although the embodimentsherein describe the conductive substrate as typically comprising ap-type substrate having at least one n-type doped region, the conductivesubstrate can also be an n-type substrate having at least one p-typedoped region. In addition, all of the embodiments herein can alsoinclude a first cladding layer having a lens portion, as providedhereinbefore. Furthermore, although luminous devices hereinbeforedescribed are utilized, any suitable vertical-type luminous device canbe substituted in, thereby utilizing the embedded zener diode in theconductive substrate 200.

FIG. 15 provides a circuit diagram illustrating the functional aspectsof the luminous device and the zener diode. The conductive substrate 200is doped with a compound that is a conductive type opposite to theconductive type of the conductive substrate. For example, when a p-typesubstrate 200 is used, selected portions of the substrate are doped withan n-type compound, and vice versa, to create the zener diode. The dopedregions of the conductive substrate 200 are then placed in electricalcommunication with the second cladding layer 116 of a luminous structure110, which is the same semiconductor type as the conductive substrate200. For example, an n-typed doped region of the conductive substrate200 is placed in electrical communication with the p-type cladding layer116 of a luminous structure 110. It is believed that the zener diodeeffectively protects the luminous structure 110 from harmful surges inreverse bias voltage, e.g., from electrostatic discharge.

FIG. 16A illustrates one embodiment of a luminous device 8 comprising azener diode. The luminous device 8 illustrated in FIG. 16A issubstantially similar to the luminous device 1 illustrated in FIG. 5.However, the luminous device 8 includes a zener diode comprising ap-type conductive substrate 200 b having an n-type doped region 205.Furthermore, the first cladding layer 112 b is n-type, and the secondcladding layer 116 b is p-type. Accordingly, when harmful reverse biasvoltages enter n-type doped region 205, it will flow harmlessly into thep-type substrate 200 b and protect the luminous structure 110. When anintermediate layer 210 is used, as illustrated in FIG. 16A, theintermediate layer is only in electrical communication with doped region205, i.e., the intermediate layer 210 should not contact the undopedregions of the conductive substrate 200 b.

Similarly, FIG. 16B illustrates another embodiment of a luminous device9 comprising a zener diode. The luminous device 9 having a grooveillustrated in FIG. 16B is substantially similar to the luminous device2 illustrated in FIG. 8. However, the luminous device 9 includes a zenerdiode comprising a p-type conductive substrate 200 b and an n-type dopedregion 205. Furthermore, the first cladding layer 112 b is n-type, andthe second cladding layer 116 b is p-type. Accordingly, when harmfulreverse bias voltages enter n-type doped region 205, it will flowharmlessly into the p-type substrate 200 b and protect the luminousstructure 110. When an intermediate layer 211 is used, as illustrated inFIG. 16B, the intermediate layer should only be in electricalcommunication with doped region 205, i.e., the intermediate layer 211should not contact the undoped regions of the conductive substrate 200b.

These luminous devices 8 and 9 can be obtained by including additionalprocess steps to the hereinbefore described methods for manufacturing avertical-type luminous device and a vertical-type luminous device havinga groove. The additional process steps can include the following: (i)doping the conductive substrate with the appropriate dopant (e.g.,opposite conductive type to the substrate) in selected regions that arein electrical communication with the portion of the first electrodelayer corresponding to the recess 121 in insulating layer 120; (ii)optionally forming a patterned conductive intermediate layer 210 (and211 for the luminous device having a groove) on the doped regions 205 ofthe conductive substrate 200 b; (iii) aligning and attaching the dopedregions 205 or the patterned conductive intermediate layer 210(corresponding to the doped regions 205) with the portion of the firstelectrode layer corresponding to the recess 121 in insulating layer 120;and any combination of the steps thereof. The patterned conductiveintermediate layer 210 is preferably formed within the doped regions 205so as not to be in contact (or in direct electrical communication) withthe undoped regions of the conductive substrate 200 b.

The present invention is also directed to luminous packages (e.g., chipscale packages) comprising the vertical-type luminous deviceshereinbefore described. These packages can be utilized in any suitableluminous system by connecting the packages to a power source. Since thedirectionality of the emitted light can be substantially controlled inthe luminous packages described herein, chip scale packaging can besubstantially simplified. Although traditional packages (e.g., includinga reflector or reflective side and back surfaces) can be used, suchtraditional packaging is not required, since the luminous packagesdescribed herein already are capable of substantially controlling thedirectionality of the emitted light. Luminous packages can be dividedinto two large categories: unencapsulated and capsulated. As usedherein, reference number 300 is a submount, which is a substrate havingat least two conductive regions for supplying electricity to theluminous device. Nonlimiting examples of a submount include a circuitboard or a printed circuit board. For simplicity, however, referencenumber 300 is referred to here in as a circuit board.

FIGS. 17 and 18 illustrate one embodiment of an unencapsulated luminouspackage 10, which comprises a luminous device 1 bound to a firstconductive region 310 (also called a contact) on a circuit board 300.The circuit board 300 also includes a second conductive region 320 (alsocalled a contact) on the circuit board 300, and a wire 330 provideselectrical communication (e.g., a wire bond) between the secondelectrode 150 and the second conductive region 320. This embodimentrequires only one wire 330 electrical connection, because the secondelectrical connection is provided by the conductive substrate 200 by wayof conductive intermediate layer 210, if utilized. Although luminousdevice 1 is substantially the same as the device illustrated in FIG. 5,any of the hereinbefore described luminous devices can be substituted infor luminous device 1 in this embodiment.

FIGS. 19, 20, 21A, and 21B illustrate various embodiments of anunencapsulated luminous package comprising a luminous device having azener diode. Although these embodiments describe the use of luminousdevices hereinbefore described, any suitable vertical-type luminousdevice can be substituted in, thereby utilizing the embedded zener diodein the conductive substrate 200.

FIG. 19 illustrates another embodiment of an unencapsulated luminouspackage 11 comprising a luminous device 8 having a zener diode, whichdevice is bound to a first conductive region 310 on a circuit board 300.The luminous device 8 has a p-type conductive substrate 200 b with ann-type doped region 205. A conductive intermediate layer 210 (i)enhances the bond between a surface of a first electrode 140 (of theluminous structure 110) and the p-type second substrate 200 b and (ii)covers (or contacts) at least a portion of the n-type doped region 205of p-type conductive substrate 200 b. The intermediate layer 210 is onlyin electrical communication with doped region 205, i.e., theintermediate layer 210 should not contact the undoped regions of theconductive substrate 200 b. A first wire 330 provides electricalcommunication between a second electrode 150 (of the luminous structure110) and the first conductive region 310, and a second wire 332 provideselectrical communication between conductive intermediate layer 210 and asecond conductive region 320 on the circuit board 300.

FIG. 20 illustrates another embodiment of an unencapsulated luminouspackage 12 comprising a luminous device 9 having a zener diode, whichdevice is bound to a first conductive region 310 on a circuit board 300.The luminous device 9 includes luminous structure 110 having a lightemitting major portion 110 a and a minor portion 110 b on which a secondelectrode 150 is disposed. Luminous device 9 also has a p-typeconductive substrate 200 b with an n-type doped region 205, assubstantially illustrated in FIG. 16B. A first conductive intermediatelayer 210 (i) enhances the bond between a surface of a first electrode140 (located on the light emitting major portion 110 a of the luminousstructure 110) and the p-type conductive substrate 200 b and (ii) covers(or contacts) at least a portion of the n-type doped region 205 ofp-type conductive substrate 200 b. The intermediate layer 210 is only inelectrical communication with doped region 205, i.e., the intermediatelayer 210 should not contact the undoped regions of the conductivesubstrate 200 b. A second conductive intermediate layer 211 enhances thebond between a surface of a first electrode 140 (located on the minorportion 110 b of the luminous structure 110) and the p-type substrate200 b. The first and second conductive intermediate layers 210, 211 canbe made of the same material or different materials. It is preferable toprovide a gap between the first and second conductive intermediatelayers 210, 211. A first wire 330 provides electrical communicationbetween a second electrode 150 (located on the minor portion 110 b ofthe luminous structure 110) and the first conductive region 310, and asecond wire 332 provides electrical communication between conductiveintermediate layer 210 and a second conductive region 320 on the circuitboard 300.

Luminous package 11 (illustrated in FIG. 19) and luminous package 12(illustrated in FIG. 20) can be utilized in a substantially similar way.Luminous package 11 and luminous package 12 are activated (e.g., to emitlight) by place a forward bias on the luminous package, e.g., placing anegative bias on the first conductive region 310 and a positive bias onthe second conductive region 320. The electrons flow from firstconductive region 310 to the second electrode 150 via first wire 330, asillustrated by the dashed arrows on the left side of FIGS. 19 and 20.When a reverse bias is placed on the luminous package, e.g., placing apositive bias on the first conductive region 310 and a negative bias onthe second conductive region 320, electrons will flow from the secondconductive region 320 to conductive intermediate layer 210. When thevoltage in reverse bias reaches a certain breakdown voltage (e.g.,dangerous levels of electrostatic discharge), the zener diode (i.e., then-type doped region 205 and the p-type conductive substrate 200 b) willallow flow of electrons through the n-type doped region 205 and thep-type conductive substrate 200 b and exit through first conductiveregion 310, thereby protecting the luminous device 8, 9.

FIG. 21A illustrates another embodiment of an unencapsulated luminouspackage 13 comprising a modified luminous device 9′ having a zenerdiode, which device is bound to a first conductive region 310 on acircuit board 300. The luminous device 9′ includes luminous structure110 having a light emitting major portion 110 a and a minor portion 110b on which a second electrode 150 is disposed, as substantiallyillustrated in FIG. 16B for luminous package 9. However, this luminousdevice 9′ is modified, because (i) it includes a through via contact 145in the minor portion of the luminous structure instead of a secondelectrode 150 and (ii) the first electrode layer 140 is removed in thearea between the major portion 110 a and minor portion 110 b of theluminous structure 110. The through via 145 contacts and extends fromthe n-type first cladding layer 112 b to the exterior of the insulatinglayer 120. The through via 145 can include a central conductive materialand optionally an outer insulation layer (not shown). Through vias canbe formed by any method known in the art. Nonlimiting examples ofacceptable processes for forming through vias can be found in U.S. Pat.No. 6,916,725 issued on Jul. 12, 2005 to Yamaguchi and titled “Methodfor Manufacturing Semiconductor Device, and Method for ManufacturingSemiconductor Module, U.S. Pat. No. 7,193,297 issued on Mar. 20, 2007 toYamaguchi and titled “Semiconductor Device, Method for Manufacturing theSame, Circuit Substrate and Electronic Device”, and U.S. Pat. No.7,214,615 issued on May 8, 2007 to Miyazawa and titled “Method ofmanufacturing semiconductor device, semiconductor device, circuitsubstrate and electronic apparatus,” which are all incorporated hereinby reference in their entirety.

Luminous device 9′ also has a p-type conductive substrate 200 b with afirst n-type doped region 205 and a second n-type doped region 206. Afirst conductive intermediate layer 210 (i) enhances the bond between asurface of a first electrode 140 (located on the major portion 110 a ofthe luminous structure 110) and the p-type conductive substrate 200 band (ii) covers (or contacts) at least a portion of the first n-typedoped region 205 of p-type conductive substrate 200 b. Similarly, asecond conductive intermediate layer 211 (i) enhances the bond between asurface of a first electrode 140 (located on the minor portion 110 b ofthe luminous structure 110) and the p-type conductive substrate 200 band (ii) covers (or contacts) at least a portion of the second n-typedoped region 206 of p-type conductive substrate 200 b. The intermediatelayer 210 is only in electrical communication with the first n-typedoped region 205, i.e., the intermediate layer 210 should not contactthe undoped regions of the conductive substrate 200 b, and theintermediate layer 211 is only in electrical communication with secondn-type doped region 206. The first and second conductive intermediatelayers 210, 211 can be made of the same material or different materials.In this embodiment, a gap is provided between the first and secondconductive intermediate layers 210, 211. The through via 145 provideselectrical communication between the n-type first cladding layer 112 b(located in the minor portion 110 b of the luminous structure 110) andthe first conductive region 310 via the second conductive intermediatelayer 211 and the second n-type doped region 206 of conductive substrate200 b, and a wire 332 provides electrical communication betweenconductive intermediate layer 210 and a second conductive region 320 onthe circuit board 300.

FIG. 21B illustrates another embodiment of an unencapsulated luminouspackage 14 comprising a modified luminous device 9″ having a zenerdiode, which device is bound to a first conductive region 310 on acircuit board 300. Luminous package 14 of this embodiment issubstantially similar to luminous package 13 illustrated in FIG. 21A.Accordingly, the description for luminous package 13 discussedhereinbefore also applies to luminous package 14. However, the p-typeconductive substrate 200 b of luminous device 14 has a through viacontact 212 instead of a second n-type doped region 206. The through viacontact 212 can include a central conductive material and optionally anouter insulation layer (not shown) As a result, the second conductiveintermediate layer 211 (i) enhances the bond between a surface of afirst electrode 140 (located on the minor portion 110 b of the luminousstructure 110) and the p-type conductive substrate 200 b and (ii) is inelectrical communication (or contact) with through via contact 212 inp-type conductive substrate 200 b.

Luminous device 9′ (illustrated in FIG. 21A) and 9″ (illustrated in FIG.21B) can be obtained by modifying the hereinbefore described methods formanufacturing (i) a vertical-type luminous device having a groove(luminous device 2 illustrated in FIG. 8) and (ii) a vertical-typeluminous device having a groove and a zener diode (luminous device 8illustrated in FIG. 16B). Two common additional process steps for bothluminous devices 9′ and 9″ can include the following: (i) locallyremoving the first electrode layer 140 from at least a portion of thegroove area 118 (e.g., the area between the major portion 110 a andminor portion 110 b of the luminous structure 110) to disconnect thefirst electrode layer 140 of the major portion 100 a from the minorportion 100 b or forming a patterned first electrode layer disconnectedin the groove area 118; and (ii) forming a through via contact 145(e.g., forming a via up to the first cladding layer 112 and filling thevia with a conductive material) in the minor portion 110 b of luminousstructure 110 before or after forming the first electrode layer, asillustrated in FIG. 6B. These additional steps are conducted beforebonding to the second conductive substrate 200.

The process step of “locally removing and disconnecting the firstelectrode layer 140 from at least a portion of the groove area 118” isconducted to prevent electrical communication through the firstelectrode layer 140 between the minor portion 110 b and major portion100 a of the luminous structure 110, thereby preventing electricalshorts within the device. Accordingly, an alternative method includesforming a patterned first electrode layer 140, wherein the patternedfirst electrode layer is a separate first electrode layer 140 for themajor portion 100 a and a separate first electrode layer 140 for theminor portion 100 b, thereby preventing electrical communication betweenthe major and minor portions of the luminous structure. In a furtheralternative method, the patterned first electrode layer 140 can beformed only on the major portion 100 a and not on the minor portion 110b.

For luminous device 9′ (FIG. 21A) additional process steps can includethe following: (i) doping (e.g., by ion implantation) an additionalregion 206 (corresponding to the minor portion 110 b of the luminousstructure) of the conductive substrate 200 b in addition to thepreviously described doping of the region 205 before bonding theconductive substrate; (ii) optionally forming patterned conductiveintermediate layers 210 and 211 within the doped regions 205 and 206 ofthe conductive substrate 200 b; (iii) aligning and attaching thepatterned conductive intermediate layers 210 and 211 (corresponding tothe doped regions 205 and 206) with the portion of the first electrodelayer corresponding to the recess 121 in insulating layer 120 andthrough via contact 145; and any combination of the steps thereof. Atleast a portion of the doping process for doped region 206 can beconducted simultaneous with the doping process for the doped region 205,and/or the doping process for doped region 206 can be conducted in aseparate process step. Furthermore the conductive substrate 200 b can bethinned at a later stage (e.g., after bonding) to allow doped region 206to be exposed on both sides of conductive substrate 200 b.

For luminous device 9″ (FIG. 21B) additional process steps can includethe following: (i) forming a through via contact 212 (e.g., forming avia through conductive substrate 200 b and filling the via with aconductive material) corresponding to the minor portion 110 b ofluminous structure 110, before or after forming doped region 205; (ii)optionally forming patterned conductive intermediate layers 210 and 211within the doped region 205 of the conductive substrate 200 b andcorresponding to the through via contact 212; (iii) aligning andattaching the patterned conductive intermediate layers 210 and 211(corresponding to the doped region 205 and through via contact 212) withthe portion of the first electrode layer corresponding to the recess 121in insulating layer 120 and through via contact 145; and any combinationof the steps thereof.

Luminous package 13 (illustrated in FIG. 21A) and luminous package 14(illustrated in FIG. 21B) can be utilized in a substantially similar wayto the hereinbefore described luminous package 12. Luminous package 13and luminous package 14 are activated (e.g., to emit light) by place aforward bias on the luminous package, e.g., placing a negative bias onthe first conductive region 310 and a positive bias on the secondconductive region 320. The electrons flow from first conductive region310 to the through via contact 145 by way of the second n-type dopedregion 206 or through via contact 212, as illustrated by the dashedarrows on the left side of FIGS. 21A and 21B. When a reverse bias isplaced on the luminous package, e.g., placing a positive bias on thefirst conductive region 310 and a negative bias on the second conductiveregion 320, electrons will flow from the second conductive region 320 toconductive intermediate layer 210. When the voltage in reverse biasreaches a certain breakdown voltage (e.g., dangerous levels ofelectrostatic discharge), the zener diode (i.e., the n-type doped region205 and the p-type conductive substrate 200 b) will allow flow ofelectrons through the n-type doped region 205 and the p-type conductivesubstrate 200 b and exit through first conductive region 310, therebyprotecting the luminous device 9′, 9″.

The embodiments illustrated in FIGS. 19-21B can further include surfacetexturing (not shown) on the light emitting surface or one lens or aplurality of lenses on the light emitting surface.

FIG. 22 illustrates another embodiment of an unencapsulated luminouspackage 15, which comprises a luminous device 1 bound to a firstconductive region 310 on a circuit board 300. This embodiment is similarto the embodiment illustrated in FIGS. 17 and 18. Accordingly, likereference numbers identify the same elements (or structures) of thepackage. The circuit board 300 in this embodiment, however, includes (i)a first surface having the previously described first conductive region310 and second conductive region 320 and (ii) a second surface having athird conductive region 312 and a fourth conductive region 322. Thecircuit board 300 further includes (a) at least one first through via316 connecting the first conductive region 310 and the third conductiveregion 312 and (b) at least one second through via 326 connect thesecond conductive region 320 and the fourth conductive region 322. Thisparticular embodiment is beneficial since the through vias 316, 326allow connection to an external device (e.g., a power source) withoutrequiring additional connections.

FIGS. 23A-23D illustrate various encapsulated embodiments, i.e.,encapsulated luminous packages 16-19. Although these figures illustratethe use of the unencapsulated package 10 (illustrated in FIGS. 17 and18), any of the previously described packages can be similarlyencapsulated. Encapsulation provides at least the following benefits:(i) a physical barrier serving as a protection; and (ii) the ability toentrap phosphors, thereby allowing control of the wavelengths of light(e.g., color) being emitted. One or more layers of encapsulation can beused.

Any appropriate encapsulate known to the skilled artisan can be used.Useful materials for encapsulants include, but are not limited to,epoxy, silicone, rigid silicone, urethane, oxethane, acryl,poly-carbonate, polyimide, mixtures thereof, and combinations thereof.It is preferred to use an encapsulant that is (i) substantiallytransparent to maximize light emission and (ii) flowable in its uncuredstate.

Similarly, any appropriate phosphor known to the skilled artisan can beused. Appropriate examples of useful phosphors can be found in U.S. Pat.No. 5,998,925 issued on Dec. 7, 1999 to Shimizu et al. and titled “LightEmitting Device Having a Nitride Compound Semiconductor and a PhosphorContaining a Garnet Fluorescent Material,” U.S. Pat. No. 7,297,293issued on Nov. 20, 2007 to Tamaki et al. and titled “Nitride Phosphorand Production Process Thereof, and Light Emitting Device,” U.S. Pat.No. 7,247,257 issued on Jul. 24, 2007 to Murazaki et al. and titled“Light Emitting Device,” U.S. Pat. No. 7,301,175 issued on Nov. 27, 2007to Izuno et al. and titled “Light Emitting Apparatus and Method ofManufacturing the Same,” U.S. Pat. No. 6,066,861 issued on May 23, 2000to Hohn et al. and titled “Wavelength-Converting Casting Composition andIts Use,” U.S. Pat. No. 6,812,500 issued on Nov. 2, 2004 to Reeh et al.and titled “Light-Radiating Semiconductor Component with a LuminescenceConversion Element,” U.S. Pat. No. 6,417,019 issued on Jul. 9, 2002 toMueller et al. and titled “Phosphor Converting Light Emitting Diode,”U.S. Pat. No. 6,891,203 issued on May 10, 2005 to Kozawa et al. andtitled “Light Emitting Device,” U.S. Pat. No. 7,157,746 issued on Jan.2, 2007 to Ota et al. and titled “Light Emitting Device Having aDivalent-Europium-Activated Alkaline Earth Metal OrthosilicatePhosphor,” and U.S. Pat. No. 6,809,347, issued to Tasch et al. andtitled “Light Source Comprising Light-Emitting Element,” which are allincorporated herein by reference in their entirety. As discussedhereinbefore, phosphors can convert at least a portion of the lightgenerated by the luminous device into another wavelength of light,thereby allowing changes in the color of light being emitted. Forexample, white light can be obtained by utilizing a luminous structureemitting blue light and using a phosphor comprising a yellow fluorescentmaterial. Similarly, red phosphor can be utilized to increase the colorrendering index.

FIG. 23A illustrates an encapsulated luminous package 16 comprising theluminous package 10, a phosphor region 340 including a plurality ofphosphor particulates 344 encapsulated in a first encapsulant 342, and asecond encapsulant 350 encapsulating the phosphor region 340. The firstand second encapsulants 342, 350 can be made of the same material ordifferent materials. It is believed that the second encapsulant 350 canprevent damage (e.g., caused by moisture) to phosphor region 340.

FIG. 23B illustrates an encapsulated luminous package 17 comprising theluminous package 10, a phosphor layer 344, and an encapsulant 350. Athin phosphor layer 344 can be sprayed onto the unencapsulated package11 before encapsulating the phosphor coated package.

FIG. 23C illustrates an encapsulated luminous package 18 comprising theluminous package 10, a phosphor layer 344, an encapsulant 342, and amodified circuit board 300 having vertically extending side walls 301.Although side walls 301 of the circuit board 300 are straight, sidewalls 301 can be angled to increase light reflectance and emission. Inthis embodiment, the side walls 301 are preferably reflective. Asillustrated, this embodiment can be utilized without an encapsulant,especially when the luminous package 18 is utilized within an enclosedlighting system. Alternatively, an encapsulant (not shown) and/or aphosphor (not shown) can be added into the enclosure created by circuitboard 300 and side walls 301, as previously described.

FIG. 23D illustrates an encapsulated luminous package 19 comprising theluminous package 10 encapsulated by a first encapsulant 342, a phosphorlayer 344 covering the first encapsulant 342, and a second encapsulant350 encapsulating the first encapsulant 342 covered by the phosphorlayer 344. The first and second encapsulants 342, 350 can be made of thesame material or different materials. It is believed that the secondencapsulant 350 can prevent damage (e.g., caused by moisture) tophosphor layer 344.

FIGS. 24-26 provide various package configurations providing arrays ofluminous devices 1. FIG. 24 illustrates an array of luminous devices 1,wherein subgroups of luminous devices 1 are placed in series. Theluminous devices in each subgroup are bound to a common first conductiveregion 310 on a circuit board 300. The second electrode 150 of eachluminous device 1 in each subgroup is electrically connected to a commonsecond conductive region 320 on the circuit board 300. FIG. 25illustrates such an array of luminous devices 1, wherein each subgroupof luminous devices 1 placed in series is encapsulated by a commonphosphor region 340 and/or a common second encapsulate 350. FIG. 26illustrates such an array of luminous devices 1, wherein each luminousdevice is individually encapsulated by a phosphor region 340 and/or asecond encapsulate 350.

FIGS. 27-31 illustrate lighting systems comprising the luminous packagesand luminous devices of the present invention. FIG. 27 illustrates anLCD panel comprising (i) a luminous package 18 including at least oneluminous device 1 mounted on a circuit board 300 having reflectivesidewalls 301, (ii) a reflective sheet 412 having patterns 412 a, thereflective sheet angled to control reflection of light in apredetermined direction, (iii) a transfer sheet 410, (iv) a spreadingsheet 414, (v) at least one prism sheet 416, and (vi) a display panel450. The reflective sidewalls 301 are not necessary when using theluminous device 1, which provide directional control of the emittedlight.

FIG. 28 illustrates a projection system comprising (i) a light source410 including a luminous package, as described herein, (ii) a condensinglens 420, (iii) a color filter 430, (iv) a sharpening lens 440, (v) aDigital Micromirror Device 450, and (vi) a projection lens 480. Theresulting image is projected onto a screen 490.

Similarly, FIGS. 29-31 respectively illustrate a headlight of anautomobile having luminous packages 10, a street lamp having at leastone luminous package 10, and an flood light having at least one luminouspackage 10.

What is claimed is:
 1. A light emitting device, comprising: a substratehaving a first through-via and a second through-via, wherein each of thefirst through-via and the second through-via extends from a firstsurface of the substrate to a second surface of the substrate oppositethe first surface of the substrate; and a luminous structure on thefirst surface of the substrate, the luminous structure having a firstcladding layer, an active layer, a second cladding layer, and aninsulated through-via contact connected to the first through-via.
 2. Thedevice of claim 1, wherein the insulated through-via contact extendsfrom the second cladding layer to the first cladding layer.
 3. Thedevice of claim 2, wherein the insulated through-via electricallyconnects the first cladding layer with the first through-via.
 4. Thedevice of claim 1, further comprising an electrode connecting the secondcladding layer with the second through-via.
 5. The device of claim 1,wherein the substrate includes a first conductive region and a secondconductive region attached to the second surface of the substrate, andwherein the first conductive region is connected to the firstthrough-via.
 6. The device of claim 1, further comprising a conductivesubstrate between the substrate and the luminous structure.
 7. Thedevice of claim 6, wherein the conductive substrate comprises a portionof a doped region.
 8. The device of claim 7, wherein the second claddinglayer is connected to the doped region.
 9. The device of claim 7,wherein the doped region is electrically connected to the secondthrough-via by wiring.
 10. The device of claim 6, wherein the conductivesubstrate includes a third through-via passing through the conductivesubstrate.
 11. The device of claim 10, wherein the third through-via isconnected to the first through-via.
 12. The device of claim 1, whereinthe luminous structure has at least one groove separating at least thesecond cladding layer and the active layer while provide at least acontinuous portion of the first cladding layer, and one portion of thegroove defines a major portion of the luminous structure and anotherportion of the groove defines a minor portion of the luminous structure.13. The device of claim 12, wherein the insulated through-via contactextends from the second cladding layer to the first cladding layer ofthe minor portion of the luminous structure.
 14. The device of claim 1,wherein the luminous structure has at least one inclined side surface.15. The device of claim 1, further comprising an encapsulant located onthe luminous structure.